Drop hammer



W.`H. J. FITZGERALD fET AL.

Nov. 25, 1941.

lDROP HAMMER Filled July s, vlsfsv 6 Sheets-Sheet l Reginald F. Fggerodw..H. J. FlTzGEALD ETAL 2,263,680

DROP HAMMER Filed July 8, 1957 6 Sheets-Sheet 2 Reginald F? Fggerfod NOV25, 1941- w. H. J. FITZGERALD ETL I 2,263,680 y DROP HAMMER Fild July s,1937 e sneaks-sheet :s

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DROP HAMMER Filed Julyl 8, 1937 6 Sheets-Sheet 4 NOII- 25, 1941- w. H.J. Fwzsl-:RALD l-:T AL

DROP HAMMER Filed July 8, 1957 6 Sheets-Sheet 5 VViH Reginald F?Fggerold A'TyS.

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Patented Nov. 25, 1941 2,263,680 Dnor HAMMER.

William H. J Fitzgerald and Reginald P. Fitz- `gerald, Braintree, Mass.,assignorsto Pneumatic Drop Hammer Company, Roxbury, Mass.,-a cor.-poration of Massachusetts Application July 8, 1937, Serial No. 152,544

l(Cl. 11B-.38.)

8 Claims.

This invention relates to improvements in drop hammers and the principalobject of the invention is to provide a drop hammer construction inwhich the hammer is reciprocably mounted in guides in a suitable frame,With means for `lifting the ham-mer, and means for releasing the hammerwhen raised to `permit it to drop and having means for insuringequalization of movement of the guided portions of the 'hammerthroughout the lifting movement thereof.

In usual drop hammer constructions the Weight of the `hammer issubstantially uniformly distributed with respect to a central verticalaxis and the ends of the hammer are guided in vertical ways or uponvertical columns. The vertical lifting force is applied in orapproximately in the direction of the vertical axis of the center ofgravity and as a consequence the hammer may be lifted and droppedwithout any substantial binding action between the ends of the hammerand the guides therefor.

Where, however, the hammer is unsymmetrically weighted, as for exampleby the attachment thereto of one ofthe members of the complementarydies, in which the Weight of one portion of the die, which is carried bythe hammer, very considerably exceeds the weight of other portions ofthe die, the hammer will tilt and bind in its guides when lifted byforce `which is applied -at a point or points not in the vertical axisof the center of gravity, so that the hammer will not dropl properlywithrespect to the complementary die, orwill so bind on the guides as toprevent operation of the hammer at all.

A11-object of vthe present invention is to provide means operable duringthe lifting movement of the hammer to transmit a lifting force orlifting forces, which are applied to the hammer, at a point or pointsremote `from the vertical axis of the center of gravity which willequalize the rates of movement of the guided portions of the hammer insuch manner that the hammer will be lifted vertically without bindingupon the guides and which also will insure proper maintenance of theposition of the hammer during the dropping movement thereof.

One of the principal objects of the invention is to provide a drophammer construction in which the hammer and anvil or complementary diescarried respectively by the hammer and anvil are of much greater areaand in which drop hammers of muchgreater weight may be employed than inprevious vdrop hammer constructions, such, for example, as drop hammersand diespflor shaping fenders and other parts of automobiles,

metal aeroplane wings, or other large areas of metal or the like, andparticularly those in which the dies are-of irregular contour andunsymmetrically `distributed weight.

A further object-of the invention is to provide a drop hammerconstruction in which the hammer is lifted by a plurality of liftingforces applied to different-portions of the hammer, with means for sotransmitting portions of such lifting forces that the resultants thereofwill raise the hammer vertically anduniformly throughout its e-ntirearea.

A further object of the -invention is to provide a drop `hammerconstruction of the character above specified in which the lifting forceor forces are applied to the hammer by 4fluid pressure operated meansacting upon the hammer at a point or points remote from the verticalaxis of the center of gravity of the ham-mer, in combination with meansfor so distributing the lifting `force or forces as-to insure uniformrates of movements of the guided portions of the hammer which will avoidvbinding of the hammer upon the guides.

Another object-of the invention is `to provide a drop hammerconstruction in which the hammer is pushed upwardly by `a iluidpressureoperated means Yactingl upon vthe en d portions of the hammer.

Anotherfeature of theinvention relates `to 4novel Vfluid pressureactuated mechanism for controlling the admission of fluid simultaneuslyto the cylinders of the lifting mechanism.

Another object of the invention is to provide a drop hammer for dieforging in which the hammer die is cast upon the hammer and amethod forproducing such a construction.

Another object of -the invention is `to provide pneumatically operablemeans for effectively cushioning ythe-upward movement Yof the Yhammerwhen lifted which will prevent abrupt arrest of the hammer andconsequent jarring which would tend to injure the structure.

These land other objects and `features of the invention will morevvfully appear Yfromfthe iollowing description and the accompanyingdrawings, andwill be particularly pointed out inthe claims.

V,Preferred embodiments of `the invention are illustrated in theaccompanying drawings, -=in which:

Fig. -1 ;is a fron-t elevation of a drop 'hammer embodying -theinvention in which `the hammer is lifted by two `pneumatically operatedcylinders and pistons, `the'piston rods of which lapply lifting `forcesat the ends of 'the ihammer, the

mechanism for equalizing the movements of the ends of the hammer beingomitted.

Fig. 2 is a similar View showing the frame construction in dotted lines,but illustrating in full lines the hammer, the lifting mechanismtherefor, and the equalizing mechanism for insuring equal rates ofmovement of the ends of the hammer;

Fig. 3 is a plan view of the construction shown in Fig. 2, the framebeing illustrated in dotted lines;

Fig. 4 is an end elevation of the construction illustrated in Fig. 2,the frame being shown in dotted lines;

Fig. 5 is a detail elevation, viewed from the rear, showing the valvecontrolling mechanism for admitting fluid under pressure to the liftingcylinders;

Fig. 6 is a detail elevation of the construction shown in Fig. 5, Viewedfrom the left toward the right;

Fig. 7 is a detail vertical sectional View showing the admission andexhaust valves in their relative positions for admission of fluid underpressure to the lifting cylinders;

Fig. 8 is a similar detail sectional view showing the admission andexhaust Valves in their relative positions for release of fluid underpressure from the lifting cylinders to permit the hammer to drop; and,

. Fig. 9 is a detail View showing the contour of the adjustable exhaustport for regulating the rate at which fluid under pressure is releasedfrom the cylinders thereby controlling the speed of descent of thehammer;

Fig. 10 is a detail view, partially in vertical section, on line Ill-I0Fig. 11 of a drop hammer construction illustrating the manner in whichthe hammer die is cast upon a hammer of the type illustrated herein;and,

Fig. 11 is a plan View of the hammer construction illustrated in Fig.10,

The drop hammer construction as illustrated in Fig. 1 comprises a heavyintegral bed I supporting an anvil 2 upon which an unsymmetrical die 3is mounted and a frame comprising pairs of vertical end standards 4 and5, each pair being integrally connected at their upper ends and eachstandard is provided With a pair of guides 6 and I for the hammer. Thepairs of standards are connected at their upper ends by a transversebeam 8.

The hammer 9 is provided with extended guiding members I0 and II whichare complementary to and slidably mounted upon the guides 6 and 'Irespectively. The preferred form of hammer, which is illustrated hereinas adapted for dieshaping long articles of considerable width, is ofrectangular form and is provided with a central upwardly extending bossI2 with vertical webs I3 and I4 extending radially therefrom to theguides I Il and I I and other webs I5 extending to the edge of thehammer at right angles to the longitudinal axis thereof. The ends of thehammer are provided with extensions I6 and I'I which project outwardlybetween and beyond the respective pairs of guides I0 and II and thelifting forces for raising the hammer are applied to such extensions.The hammer as illustrated has secured to it a die I8 which iscomplementary to the anvil die 3 and as will be observed is of muchgreater weight at one end than the other.

The complementary dies may be of any suitable form and shape and may beof steel, but

where a limited number of parts are to be shaped the dies may be made ofrelatively soft metal, usually of different hardness, such as an anvildie of Zinc or bronze composition and a complementary die of lead orother relatively softer metal.

The anvil die may be constructed by forming a matrix of plaster of Parisor the like and shaping the operating face to the desired contour andornamentation. The harder metal for the anvil die may then be cast uponthis matrix. When the matrix is removed the die may be turned over andsuitably secured to the anvil.

By the present invention the hammer die may then be cast directly uponthe hammer itself by a method hereinafter to be described.

By reason of this invention a hammer die is produced which iscomplementary in all respects to the anvil die and adapted to registeraccurately with the same during the period of its use. Such dies may beused for shaping relatively ductile metal, such as aluminum, orrelatively thin sheets of steel and the like for a more or less limitednumber of times. The dies constructed in this manner are usedparticularly in the production of large die-shaped pieces where alimited number of different sizes or different contours are frequentlyrequired.

In such drop hammer constructions the vertical axis of the center ofgravity of the hammer is ordinarily remote from the central verticalaxis of the hammer and inasmuch as one end of the hammer is of greaterWeight than the other end or portion of the hammer, there will be atendency of the hammer to bind upon its guides as the hammer is lifted,by a force or forces applied to the hammer at points out of alinement ofthe vertical axis of the center of gravity of the hammer.

The particular drop hammer construction il lustrated herein is designedfor the shaping of large areas of metal and the hammer may be of severaltons weight. In order properly to lift such a hammer pneumaticallyoperated means are preferably provided for simultaneously lifting bothends of the hammer, with means for equalizing the rate of movement ofthe guided portions of the hammer which will prevent binding of thehammer upon its guides. The lifting mechanism illustrated comprises apair of vertical pneumatic cylinders I9 and 20 which are located at theends of the base and are provided with pistons having respectivelypiston rods 2| and 22, the upper ends of which engage the under faces ofthe extensions I6 and I'I of the hammer. Suitable 'means hereinafter tobe more fully described are provided for simultaneously admitting fluidunder pressure to the lifting cylinders I9 and 20 and for releasing thefluid pressure to permit the hammer to drop.

Suitable force-transmitting means are provided which act upon movementof the hammer to cause equality of movement of both guided ends of thehammer. In the particular construction illustrated suchforce-transmitting means comprises one or preferably a plurality of tautinextensible flexible members each of which is connected to both ends ofthe hammer, with means for guiding the respective sections of eachflexible member adjacent its attachment to the hammer in oppositevertical directions so that if a preponderance of force is applied tothe lighter portion of the hammer, such portion of said force will betransmitted to the heavier portion of the hammer as to cause both endsof the hammer to be lifted at an equal `rate of speed and Aconversely ifa preponderance of forceis applied -to the heavier portion of thevhammer 4-the lighter portion of the ham-mer will be caused Ato `movelupwardly Aat the same rate -of speed.

1n itheparticular construction illustra-ted a taut inflexible`Inomics-zr 23 'isrigidly secured at one Vend to za boss 24 upontheextension I=1 of -t-he hammer and has la section *25 extendingvertically `upwardly therefrom vover a 1sheave /26 which Vis mounted`upon fthe fbeam i8 and thence 'horizontally over a sheave 21 mountedIupon the other end .por-tion of the beam E8, thence downwardlyagainst-a guide sheave A28 which is mounted nupon the `upper fendportion of 'the standard 4, thence downwardly aroundasheave 219 which.iis mounted on the lower `portion of the standard `4, thence upwardly-`through :a boss 230 Vto which its end vis adjustabllysecured, fso that:this end portion '3'I of the infiexible member 22'3 1as vwell as theend section 123 `extends vertically. IThe sheaves 7.6 and 219 are .so`positioned as to direct the Aend vsections 25 and 34 respectivelyAvertically a -distance at least Las great yas the `distance .through`which the hammer drops.

While fa :single ztaut inextensible iiexible member :may be employed,zdesirably `a plurality of such members :are embodied in the machine. Asillustrated herein fa complementary taut inextensible .lflexible vmember32 has Aone lend connected toa :boss 33 fon theiextension I1 olf thehammer. The :end lsection .34 thereof extends vertically downwardlyaround a sheave35 mounted fon the lower portion ofthe standard '4,thence upwardly along :a guiding sheave :36 mounted `upon the upperportion of 'the standard 4, 'thence over a sheave 3f1 which .is 'mountedvupon .the beam 8, thence horizontally:overa-sheave 38, then verticallydownwardly, the end section 39 being adjustably Yconnected tto Ia boss'40 .on the vextension I-6 of 'the hammer.

lBy Yreason of the :Lf-act that each ofthe comp'lementary tautlinextensible lexible :members is connected toibothfen'ds of theLhammer, `with .end sections vextending lvertically .in :oppositedirections from their points of =.connec'tion I.to the :hammer, ybothends .of 'the hammer .move at equal rates of .speed :during the liftingand dropping movements lthereof and tilting of the hammer, which 4wouldcause vbinding upon the guides, is eliminated.

,Another important .object :of the .invention is to provide `'novelautomatically operable means for admitting /fluid under pressure to thecyilnders simultaneously to .raise the hammer, with manually controlled(means for releasing the `iiuid pressure from the 'cylinders to .permitthe hammer Vto drop. In the construction illustrated hereinfluid underpressure,.such yas compressed air, lis supplied from `a .suitable sourcethrough a cylindrical inlet .conduit 4I having a vsection whichdesirably extendsrhorizontally through the base of the machine toa valveblock 42 which is mounted upon the rear face Vof the base I fas shownindottedV lines in .Fig.l1 and in Fig. 6. In order Vto-permit .the use ofrotatable valves of a ccnvenientdiameter, the valve block 42 is provideduwitha `recess having a circular inlet end complementar-y to andregistering with the inlet conduit 4I, and tapering therefrom toarelatively wide somewhat-elliptical outlet 43 as shown in dottedlinesinFig. whichcommunicates with a similar routlet `in a A"horizontalvalve sleeve 44 which is mountedin the valve-block4l2. A main operating'three-way `valve 45, which fis rotatably mounted in the sleeve Y'44, isprovided with na passage '46 which extendsdiametrically therethrough andalso has a port 41 which extends radially from said passage atright-angles thereto, as =il lustrated iin Figs. 7 and `8 of thedrawings. The valve S45 is provided at its ends with trunnions whichdesirably are mounted in anti-friction bearings 4B in the sleeve 44 asAshown in dotted lines in Fig. '5. The mainoperating valve -45 and itsantifriction Vbearings are ,of the s'ame construction as `the Loperatingor control valve shown and described Jin our prior Patent No. 1,924,545'and Vparticularly as shown in Figs. 'l0 and 1l of said patent.

An exhaust valve mechanism which is also mountedin lthe valve block 42in `proximity =to the main operating valve "andas shown iin Figs. 7 and8 comprises a sleeve 429 having diametrically opposite ports' whichcommunicate respectively through a port 5,0 vvwith a corresponding portin the -sleeve 44 `and with a discharge outlet conduit 5I which may `:beprovided with `a flange 52, as shown in Fig. .51to enable *it to beconnected Yto a suitable .exhaust pipe. The `exhaust valve 53 iis ofcylindrical form .and iis provided with diametrcally opposite 'ports T54Vand 55 which register respectively with the conduit 5l) andthe outlet5I. The port 55 vof the .exhaust valve 53 desirably "is of substantiallytriangular form, .as shown .in Fig. 9, and may be rotarily adjusted tovdetermine .thev effective size .of lthe :exhaust outlet, thereby`vcontrolling the rate at Vwhich the fluid `under `pres-- sure .isvpermitted vto :escape `from the cylinders. The exhaust lvalve .53desirably iis yprovided with trunnions which are vmounted inanti-friction bearings 56 which in turn are mounted in 4.the sleeve 49,as shown in dotted lines in Fig. 5, and one of `the trunnions .of theexhaust valve 1isprovided with an 4angular vend :portion 151, see Fig. 6upon whicha'handle .member .58 is Secured, which may be vconvenientlymoved .manually `to `adjust the area of .the-exhaust outlet.

The valve block 42 is provided with a downwardly extending .passage .5.9which communicates `with .branches .6U and 6I `which in turn communicatewith .conduits =62 iand 63 .leading Vto the 'lower end portions ofthecylinders .t9 .and 2.0, as shown in Fig. 5 and in dotted lines 'inFig. 1.

In `the construction disclosed manually controlled pneumaticallyoperated means are providedor actuating the operating Valve 4.5. Thepreferred mechanism illustrated :comprisesan integral metal block 64which tissecured .to Vthe end of the valveblock 42,:as vshown Yin Fig.5, .and is provided with integral vertical alinedcylinderex` tensions 65and 66, the cylinder 65 .having a smaller diameter than that ofthecylinderi. A piston 61 in the lcylinder 65 vis connected to Yone endof a.:piston rodigthevother-iend of'saidpiston rod being connected Vtothe :piston 69 in the cylinder 66. The piston rod is provided centrallyof its 'length with enlarged annular sections between'which.complementary semi-cylindricalsections 10'of an actuatingarm 1I aresecured. .As shown'in Fig.16;.the arm .1I .extends between rollers A12and 13 which extend `inwardly lfrom y a plate 1.41which is xedly mountedupon an angular-extension 15.0f one ofthe trunnionsof'the operatingvalve 45. A small pipe 16 vleads from the :main inlet conduitlll througha `manually-operable :rotary "three-way valve 11 tothe lower end `ofthecylinder 66, as vshown in Fig. Landasimilar small pipe "18 -also leadsfrom the main `conduit 4'I to they upper endof thecylinder'65. 'The-valve 1-1 is provided with `a manuallyloperable handle P19.

By reason of this construction the cylinder 65 is supplied constantlywith fluid under pressure. When the controlling valve 11 is positionedby the handle 19 to permit the passage of fluid under pressure from thesource of fluid under pressure through the pipe 16 to the cylinder 66,the uid pressure upon the piston 69 will force the piston upwardlyagainst the constant pressure upon the piston 61 because of the greaterarea of the piston 69. It will therefore raise the arm 1I which issecured to the piston rod 68 and thereby rotate the main operating valve45 to the position illustrated in Fig. 8 in which fluid is allowed toescape from the lifting cylinders I9and 20 through the exhaust valve 53.The three-way controlling valve 11 is provided with a port which whenthe valve is restored manually to normal position communicates with anoutlet 88 in the valve casing through which air under pressure escapesfrom the section of the pipe leading from the valve 11 to the cylinder66. When therefore pressure in the section of the pipe 16, leading fromthe Valve 11 to the cylinder 66, is released, the constant fluidpressure which is supplied to the cylinder 65 will force the piston 61downwardly, thereby causing the piston rod 68 to rotate the mainoperating valve 45 to the normal position illustrated in Fig. '1,thereby supplying air under pressure from the inlet conduit 4I throughthe ports of the valve 46 and 41 to the cylinders I9 and 20 therebyraising the piston rods 22 thus lifting the hammer and maintaining it inraised position until the control Valve 11 is again actuated manually torelease the pressure in the lifting cylinders and permit the hammer todrop.

Assuming that the hammer is resting upon the anvil, the operator instarting the machine will rotate the handle 19 in a direction to causethe valve 11 to exhaust through the port 80 so that air under pressurewill be released from the cylinder 66 thereby permitting the pressure onthe piston 61 in the cylinder 65 to rotate the main operating valve tothe position illustrated in Fig. '1 in which fluid under pressure issupplied to the lifting cylinders I9 and 20. 'I'he pistons of saidcylinders will thereupon be raised, thus forcing the piston rods 2| and22 upwardly and lifting the hammer.

When it is desired to drop the hammer the handle 19 will be rotated inthe opposite direction thereby supplying fluid under pressure throughthe pipe 16 to the upper cylinder 66 so that the piston 69 will beforced upwardly by the pressure in the cylinder 66 and the mainoperating valve 45 rotated to exhaust position as shown in Fig. 8.

Desirably means are provided for admitting air under pressure to thecylinders I9 and 20 just previously to the impact of the hammer upon theanvil for the purpose of preventing a secondary blow caused by therebound of the hammer, and

. also for the purpose of applying lifting force to the hammer upon itsrebound, thereby saving a considerable amount of energy which otherwisewould be required to lift the hammer from the position of rest. This isaccomplished in the present construction by providing the controllingvalve 11 with a vertical valve stem 8I having secured to it an inclinedor preferably spiral cam 82 adapted to be engaged by one of theguideways 83 of the hammer or a suitable pin or lug 82a: projectingtherefrom. The cam 82 is adapted to be adjusted vertically upon thevalve stem 8|v in such manner as most effectively to cause admission ofair under pressure to the lifting cylinders I9 and 20 at the propermoment during rebound of the hammer.

In the operation of the drop hammer therefore the movement of the handle19 in a proper direction will cause the hammer to drop, and as thehammer descends the cam 82 will be engaged by the pin 82a: on the hammerat the proper time to rotate the controlling valve 11 to exhaustposition, thereby releasing fluid pressure from the cylinder 66 throughthe pipe 16 to cause the rotation of the main operating valve to theposition shown in Fig. 7 in which air will be supplied to the liftingcylinders, thus causing the hammer automatically to be raised andmaintained in raised position so long as air under pressure is suppliedto the cylinders I9 and 2U.

Desirably means are provided for cushioning upward movement of thehammer and to prevent vibration thereof when it is in lifted position.In the preferred construction illustrated fluid operated cushioningmeans are provided comprising a cylinder 84 extending upwardly from andpreferably integral with the central portion of the beam 8 and providedwith a head 85. A piston 86, which is reciprocably mounted in thecylinder 84, is provided with a piston rod 81, the lower end of which isadapted to be engaged by an abutment upon the hammer. In the particularconstruction shown the abutment comprises a head 88 of a screw 89 whichextends into an axial bore in the central boss I2 of the hammer. Thescrew 89 is provided with a nut 90 having suitable Spanner holes 9I bymeans of which it may be rotated to adjust the position of the head 88of the screw. The piston rod 81 may be provided with a suitable gland 92to prevent escape of fluid under pressure from the cylinder along thepiston rod 81. Fluid under pressure is led from the main pipe 4I througha branch (not shown) to a pipe 93 having branches 94 and 95 leadingrespectively to the upper and lower portions of the cylinder 84. Thebranch 94 of the pipe 93 desirably is provided with a valve 96 which maybe adjusted to restrict the rate of passage of the fluid under pressurefrom the upper section of the cylinder 84.

When in the operation of the machine the hammer is in lowered positionthe piston 86 and its piston rod 81 will descend by reason of the factthat the air under pressure supplied on opposite sides of the piston 86through the pipes S4 and 95 will be equal and the weight of the pistonand piston rod sufficient to cause it to descend. Upon upward movementof the hammer the head 88 of the screw 89 will engage the lower end ofthe piston rod 81 and during further upward movement of the hammer thepiston 86 will be forced upwardly, thereby forcing air under pressurethrough the pipe 94 and the restricted passage produced by the valve 96,thereby cushioning the upward movement of the hammer and graduallycausing it to come to rest without jarring the superstructure of theframe.

While the particular invention illustrated and described hereincomprises two lifting cylinders having pistons acting upon therespective end portions of the hammer, with means operable when thehammer is lifted or permitted to drop to equalize the rate of movementof the ends of the hammer, it is obvious that the equalizing mechanismwill operate effectively if only a single cylinder is supplied withfluid under pressure to lift the hammer, or if the lifting force isapplied to the hammer by any means at any point or points throughout thelength thereof. It is also obvious that similar equalizing means may beapplied to the hammer transversely of its 4width to prevent lateraltilting of the hammer effective operation is insured.

Another important object o-f the invention is to provide a novel processof producing an anvil die and a complementary hammer die in such manneras to provide uniformity of the complementary co-acting die surfaces andto insure accuracy of registration of all portions of the hammer diewith those of the complementary anvil die.

The anvil die may be constructed as heretofore described by casting thezinc or bronze composition in a matrix of plaster of Paris and thenremoving the matrix and turning over the die and securing it upon theanvil.

Figs. and 11 of the drawings illustrate a drop hammer having an anvilprovided with an anvil die and a hammer similar to that heretoforedescribed with the exception of the omission of `the transversereenforcing web I5 and showing the manner in which the hammer die iscast directly upon the hammer.

In order to prevent displacement of the anvil `die upon the anvil theupper surface of the .anvil desirably is provided with a series ofgrooves 91 extending both longitudinally and transversely over asomewhat larger area than the under surface of the anvil die.

A vertical frame 9B of suitable material is then placed upon the anvilclosely surrounding the periphery of the anvil die and desirably hasextensions which project into the grooves 91 of the anvil die to holdthe frame in place. The frame 9B extends above the upper surface of theanvil die the necessary distance to provide for the proper depth of thehammer die. The body of the hammer 9 is provided with a sufficientnumber of properly distributed holes to receive anchoring bolts 99 theheads of which extend a considerable distance below the under face ofthe hammer head. The hammer is also provided with inverted conical sprueholes |00 through which the lead, or other relatively soft metal may bepoured .into the frame which surrounds the anvil die. Y

In forming thehammer die the hammer is lowered gently until it restsupon the upper edge of the frame 98, with the bolts .99 depending intorthe space between the hammer and the upper surface of the anvil die.The molten lead, or other relatively soft metal, is poured through theconical sprue holes |110 until the entire chamber within the frame isfilled and until the metal overiiows through the sprue holes. Any numberof -such sprue holes may be employed and the metal poured through themsimultaneously or as rapidly as possible to -produce an integral anvilthe hammer and after the chamber of the frame has been filled withmolten metal the hammer is lowered untilthe metal is forced into thedovetail recesses and the hammer permitted to remain in such positionuntil the metal is cool. 'Ihis method is objectionable forthe reasonthat the pressure of the hammer frequently causes the excess of moltenmetal in the frame to be squirted out thus endangering the operator.Furthermore, the lowering of the cold hammer upon the molten metalchills the upper surface thereof. This method is further objectionablein that it is very difficult to remove the soit metal die from the plateto which it is secured by the insertion of wedges in the grooves whichare likely also to distort the die and unfit it for further use.

By the present method the heat of the metal transmitted to the hammerduring the pouring operation suiiiciently heats the metal of the hammerto reduce the chilling effect upon the molten metal to a minimum.Furthermore, the conical sprue holes provide risers which enable all ofthe air to escape from the chamber of the frame, thereby insuringcomplete lling of the frame and homogeneity of the metal of the hammerdie.

Inasmuch as the hammer is stationary during the pouring operation, alldanger of squirting of the metal by the previous process above describedis avoided.

By reason of the present invention the hammer die can be readily removedfrom the hammer by merely removing the nuts of the bolts and raising thehammer and when it is desired to replace the die the bolts will registerwith the holes and any slight deviation will be compensated by theengagement of the metal forming the conical protuberances IUI with thecomplementary walls of the sprue holes IBI! through which the metal hasbeen poured,

By reason of the present method therefore the hammer die can be moresafely made and when constructed in this manner is of a more homogeneouscharacter than those produced by previous methods. It is also easilyadaptedV for removal and replacementwithout distortion, and accuracy ofoperation thereby insured.

When the hammer die has been formed in the above manner, the hammer israised, the frame 98 removed, and the hammer then permitted to drop uponthe anvil die. Such dropping of the hammer will force the anvil diedownwardly so that the metal of the under face of the anvil die will bedriven into the recesses 91 in the anvil, thereby xedly positioning theanvil in place and insuring perfect registry with the hammer die duringthe die-shaping of the blanks of metal which are placed upon the anvildie.

It will be understood that the particular embodiment of the inventionshown and described herein is of an illustrative character and is notvrestrictive -of the meaning 'and scope of the following claims.Y

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is:

l. A drop hammer construction comprising a base having an anvil, a framemounted on said base having widely spaced vertical guides for the endsof the hammer, an unsymmetrically weighted hammer reciprocably mountedin said guides, vertical pneumatic cylinders mounted respectively on theend portions of said base having pistons provided with upwardlyextending piston rods engagingthe respective end portions of the hammer,means for supplying air under pressure to said cylinders to cause thepistons thereof to push the hammer upwardly, manually operable means forsimultaneously releasing the air under pressure from said cylinders topermit the hammer to drop, and means for transmitting force from one endof the hammer to the other to equalize the rate of movement of theguided end portions of the hammer throughout the lifting and droppingmovement thereof,

2. A drop hammer construction com-prising a base having an anvil, aframe mounted on said base having widely spaced vertical guides for theends of the hammer, an unsymmetrically weighted hammer reciprocablymounted in said guides, vertical pneumatic cylinders mountedrespectively on the end portions of said base having pistons providedwith upwardly extending piston rods engaging the respective end portionsof the hammer, means for supplying air under pressure simultaneously tosaid cylinders to cause the pistons thereof to push the hammer upwardly,manually operable means for simultaneously releasing the air underpressure from said cylinders to permit the hammer to drop, complementaryinextensible flexible power transmitting means each connected to bothends of sai-d hammer, and means for guiding the same to cause saidinextensible members to act upon the end portions of the hammer inopposite directions during the lifting and dropping movement thereofthereby to equalize the rates of movement of the ends of the hammer andto prevent binding action between the respective ends of the hammer' andthe guides.

3. A drop hammer construction for shaping large unsymmetrical articlescomprising a base provided with an anvil having an unsymmetrical diemounted thereon, a frame having vertical standards extending upwardlyfrom said base and provided with guides for the hammer, a cross beamconnecting the upper ends of said standards, a hammer reciprocablymounted in said guides, carrying an unsymmetrically weighted diecomplementary to said anvil die, vertical pneumatic cylinders mounted onthe end portions of said base having pistons provided with upwardlyextending piston rods connected respectively to the end portions of thehammer, means for simultaneously supplying air under pressure to saidcylinders to raise said hammer, means for releasing said air underpressure from said cylinders to permit the hammer to drop, upper sheavesmounted on said frame above the respective ends of said hammer, a lowersheave mounted upon the lower portion of one of said standards, and ataut inextensible flexible member connected at one end to the endportion of said hammer and extending vertically upwardly therefrom overan upper sheave, thence horizontally over the other upper sheave, thencedownwardly around the lower sheave, and thence vertically upwardly andconnected 'at its end to said hammer, and operable during the movementof the hammer to equalize the rates of movement of the ends of saidhammer.

4. A drop hammer construction for shaping large unsymmetrical articlescomprising a base provided with an anvil having an unsymmetrical dieYmounted thereon, a frame having vertical standards extending upwardlyfrom said base and providedwith guides for the hammer, a cross beamconnecting the upper ends of said standardsy a hammer reciprocablymounted in said guides, carrying an unsymmetrically weighted Ydiecomplementary to said anvil die, vertical pneumatic cylinders mounted onthe end portions of said base having pistons provided with upwardlyextending piston rods connected respectively to the end portions of thehammer, means for simultaneously supplying air under pressure to saidcylinders to raise said hammer. means for releasing said air underpressure from said cylinders to permit the hammer to drop, upper sheavesmounted on said frame above the respective ends of said hammer, a lowersheave mounted upon the lower portion of one of said standards, and ataut inextensible flexible member connected at one end to the endportion of said hammer and extending vertically upwardly therefrom overan upper sheave, thence horizontally over the other upper sheave, thencedownwardly around the lower sheave, and thence vertically upwardly andconnected at its end to said hammer, and a complementary tautinextensible ilexible member reversely connected in like manner to theends of said hammer and passing over similar upper sheaves and a lowersheave mounted upon the opposite standard.

5. A drop hammer construction comprising a frame having vertical guidesfor the hammer, a hammer reciprocably mounted in said guides, means forlifting said hammer including a cylinder and piston, an inlet conduitleading from a supply of air under pressure to said lifting cylinder, anoperating valve in said conduit having ports respectively to establishcommunication between said supply and said cylinder and to exhaust thefluid pressure from said cylinder, means for positioning said operatingvalve comprising oppositely disposed cylinders of different diameterprovided respectively with pistons having a common piston rod havingmeans for actuating said valve, means for simultaneously supplying airunder the same pressure from said supply of air under pressure to bothof said cylinders operable by the greater effective pressure on thelarger piston so to position said operating valve as to supply fluidunder pressure to said lifting cylinder, and manually operable means forreleasing the fluid under pressure from the larger cylinder only tocause the uid pressure in the smaller cylinder to move the operatingvalve to exhaust position.

6. In a drop hammer construction comprising a base provided with ananvil, a frame having vertical standards extending upwardly from saidbase and provided with guideways for a hammer, a hammer reciprocablymounted in said guideways, pneumatically operable means mounted on endportions of said base having means for simultaneously raising both endsof said hammer, means for supplying air under pressure to saidpneumatically operable means, and means for releasing the fluid pressurefrom said pneumatically operable means to permit the hammer to drop,means for cushioning and arresting the upward movement of said hammercomprising a cylinder mounted on said frame having a piston reciprocabletherein provided with a piston rod extending into the path of saidhammer, means for supplying fluid under pressure to said cylindercomprising branch pipes communicating with said means for supplying airunder pressure and having branches communicating respectively with theupper and lower chambers of said cylinders above and below its piston,and adjustable means in the branch leading to the upper chamber forrestricting the passage of air under pressure therethrough operab'lewhen the piston is forced upwardly by engagement of the hammer with saidpiston gradually to arrest the upward movement of said hammer byrestrictingthe ow of fluid through the branch conduit leading to theupper chamber of the cylinder and upon equalization of the pressure insaid upper and lower chambers of the cylinder to permit said piston andpiston rod to descend to normal position by virtue of the weight of saidpiston and piston rod.

7. A drop hammer construction comprising a base provided with an anvil,a frame having vertical standards extending upwardly from said base andprovided with a guideway for the hammer, a cross beam connecting theupper ends of said standards, a hammer reciprocably mounted in saidguides, vertical cylinders mounted on the ends of 'said base each havinga piston provided with a vertical piston rod oonnected to an end portionof the hammer, means for supplying uid under pressure simultaneously tosaid cylinders to raise the hammer, means for simultaneously releasingthe fluid pressure in said cylinders, and means for cushioning andarresting the upward movement of said hammer comprising a cylinderAmounted upon said beam midway of its width having a piston reciprocabletherein provided with a piston rod extending into the path of thehammer, means for supplying fluid under pressure to said cylindercomprising a pipe leading from said fluid pressure supply and havingbranch pipes communicating respectively with the upper and lower ends ofsaid cylinder, and adjustable means for restricting the passage of saidfluid under pressure through the pipe which communicates with the upperend of said cylinder.

8. A drop hammer construction as in claim '7, characterized in that thehammer is provided with an upwardly extending boss, a screw mounted insaid boss having a head forming an abutment to engage the lower end ofthe piston rod of the piston of the cushioning means and a nut for saidscrew mounted upon the upper end of said boss.

WILLIAM H. J. FITZGERALD. REGINALD P. FITZGERALD.

